China's securities regulator China Securities Regulatory Commission (CSRC) is tightening the rules for major stock sell-downs by large shareholders.

The commission said the new rules aim to prevent large shareholders from reducing their holdings in a chaotic fashion that disturbs market order and dents investor confidence.

The CSRC started controlling sell-downs during the 2015 stock market crash, but major shareholders have appeared to be accelerating sales of their stock in recent months.

Dang Ge, a spokesperson for the commission said regulating major shareholders' stock sales is an important part of a market-based trading system. He also said the CSRC has set up a group to study the regulations involving share reductions.

"We will take reference from other countries and revise the rules. We will also work with Shanghai and Shenzhen stock exchanges, to regulate share reductions from listed companies' major shareholders,” said Dang.